JP

Biogeophysical effects of historical land cover changes simulated by six Earth system models of intermediate complexity

Six Earth system models of intermediate complexity that are able to simulate interaction between atmosphere, ocean, and land surface, were forced with a scenario of land cover changes during the last millennium. In response to historical deforestation of about 18 million sq km, the models simulate a decrease in global mean annual temperature in the range of 0.13–0.25°C. The rate of this cooling accelerated during the 19th century, reached a maximum in the first half of the 20th century, and declined at the end of the 20th century. This trend is explained by temporal and spatial dynamics of land cover changes, as the effect of deforestation on temperature is less pronounced for tropical than for temperate regions, and reforestation in the northern temperate areas during the second part of the 20th century partly offset the cooling trend. In most of the models, land cover changes lead to a decline in annual land evapotranspiration, while seasonal changes are rather equivocal because of spatial shifts in convergence zones. In the future, reforestation might be chosen as an option for the enhancement of terrestrial carbon sequestration. Our study indicates that biogeophysical mechanisms need to be accounted for in the assessment of land management options for climate change mitigation.

© Springer

Biomass Energy and Competition for Land

We describe an approach for incorporating biomass energy production and competition for land into the MIT Emissions Prediction and Policy Analysis (EPPA) model, a computable general equilibrium model of the world economy, that has been widely used to study climate change policy. We examine multiple scenarios where greenhouse gas emissions are abated or not. The global increase in biomass energy use in a reference scenario (without climate change policy) is about 30 EJ/year by 2050 and about 180 EJ/year by 2100. This deployment is driven primarily by a world oil price that in the year 2100 is over 4.5 times the price in the year 2000. In the scenarios of stabilization of greenhouse gas concentrations, the global biomass energy production increases to 50-150 EJ/year by 2050 and 220-250 EJ/year by 2100. The estimated area of land required to produce 180-250 EJ/year is about 2Gha, which is an equivalent of the current global crop area. In the USA we find that under a stringent climate policy biofuels could supply about 55% of USA liquid fuel demand, but if the biofuels were produced domestically the USA would turn from a substantial net exporter of agricultural goods ($20 billion) to a large net importer ($80 billion). The general conclusion is that the scale of energy use in the USA and the world relative to biomass potential is so large that a biofuel industry that was supplying a substantial share of liquid fuel demand would have very significant effects on land use and conventional agricultural markets.

(Chapter available by request)

About the book: Land has long been overlooked in economics. That is now changing. A substantial part of the solution to the climate crisis may lie in growing crops for fuel and using trees for storing carbon. This book investigates the potential of these options to reduce greenhouse gas emissions, estimates the costs to the economy, and analyses the trade-offs with growing food. The first part presents new databases that are necessary to underpin policy-relevant research in the field of climate change while describing and critically assessing the underlying data, the methodologies used, and the first applications.

Together, the new data and the extended models allow for a thorough and comprehensive analysis of a land use and climate policy. This book outlines key empirical and analytical issues associated with modelling land use and land use change in the context of global climate change policy. It places special emphasis on the economy-wide competition for land and other resources, especially;

  • The implications of changes in land use for the cost of climate change mitigation,
  • Land use change as a result of mitigation, and
  • Feedback from changes in the global climate to land use.

By offering synthesis and evaluation of a variety of different approaches to this challenging field of research, this book will serve as a key reference for future work in the economic analysis of land use and climate change policy.

© 2009 Routledge

Biomass Energy and Competition for Land

We describe an approach for incorporating biomass energy production and competition for land into the MIT Emissions Prediction and Policy Analysis (EPPA) model, a computable general equilibrium model of the world economy, that has been widely used to study climate change policy. We examine multiple scenarios where greenhouse gas emissions are abated or not. The global increase in biomass energy use in a reference scenario (without climate change policy) is about 30 EJ/year by 2050 and about 180 EJ/year by 2100. This deployment is driven primarily by a world oil price that in the year 2100 is over 4.5 times the price in the year 2000. In the scenarios of stabilization of greenhouse gas concentrations, the global biomass energy production increases to 50-150 EJ/year by 2050 and 220-250 EJ/year by 2100. The estimated area of land required to produce 180-250 EJ/year is about 2Gha, which is an equivalent of the current global crop area. In the USA we find that under a stringent climate policy biofuels could supply about 55% of USA liquid fuel demand, but if the biofuels were produced domestically the USA would turn from a substantial net exporter of agricultural goods ($20 billion) to a large net importer ($80 billion). The general conclusion is that the scale of energy use in the USA and the world relative to biomass potential is so large that a biofuel industry that was supplying a substantial share of liquid fuel demand would have very significant effects on land use and conventional agricultural markets.

Black Carbon Aerosols and Tropical Convective Precipitation

Black carbon aerosols are able to force a significant change in tropical convective precipitation ranging from the Pacific and Indian Ocean to the Atlantic Ocean, represented by an enhancement in the north portion and a reduction in the south portion of the ITCZ (e.g., Wang, 2004; Roberts and Jones, 2004; Chung and Seinfeld, 2005). This change occurs often well away from emission centers, demonstrating a "remote climate impact" of BC aerosols and suggesting that it is likely caused by forced changes in the large-scale circulation rather than local effect by BC radiative forcing. In order to investigate the detailed forcing mechanism of above impact, multiple 60-year runs using an interactive aerosol-climate model driven by various partitions of the global BC emissions have been carried out. It is found that the strength of the impact of BC aerosols emitted from a given source region on tropical rainfall is largely determined by the geographical location rather than total emission amount of that region. Interesting casual relations between BC forced tropical rainfall changes over different regions and BC emissions from various continents/major source regions will be discussed. Generally speaking, despite the differences in pattern and strength, the results of this study suggest that BC aerosols emitted from each of the major source regions can all cause an alternation to tropical convective rainfall, implying that cutting emissions from any region alone can not eliminate this climatic effect of BC aerosols.

Black Carbon and West African Monsoon Precipitation: Observations and Simulations

We have recently investigated large-scale co-variability between aerosol and precipitation and other meteorological variables in the West African Monsoon (WAM) region using long term satellite observations and reanalysis data. In this study we compared the observational results to a global model simulation including only direct radiative forcing of black carbon (BC). From both observations and model simulations we found that in boreal cold seasons anomalously high African aerosols are associated with significant reductions in cloud amount, cloud top height, and surface precipitation. These results suggest that the observed precipitation reduction in the WAM region is caused by radiative effect of BC. The result also suggests that the BC effect on precipitation is nonlinear.

Bringing Transportation into a Cap-and-Trade Regime

The U.S. may at some point adopt a national cap-and-trade system for greenhouse gases, and if and when that happens the system of CAFE regulation of vehicle design very likely could still be in place. Imposed independently these two systems can lead to economic waste. One way to avoid the inefficiency is to integrate the two systems by allowing emissions trading between them. Two possible approaches to potential linkage are explored here, along with a discussion of ways to guard against violation under such a trading regime of vehicle standards that may be justified by non-climate objectives. At a minimum implementation of a U.S. cap-and-trade system is several years in the future, so we also suggest intermediate measures that would gain some of the advantages of an integrated system and smooth the way to ultimate interconnection.

Canada and Alaska

About the book: This volume is a synthesis of the NASA funded work under the Land-Cover and Land-Use Change Program. Hundreds of scientists have worked for the past eight years to understand one of the most important forces that is changing our planet-human impacts on land cover, that is land use. Its contributions span the natural and the social sciences, and apply state-of-the-art techniques for understanding the earth: satellite remote sensing, geographic information systems, modeling, and advanced computing. It brings together detailed case studies, regional analyses, and globally scaled mapping efforts. This is the most organized effort made to understand the dominant force that has been responsible for changing the Earth’s biosphere.

Pages

Subscribe to JP